Climate Change and the Caribou

Climate change is impacting the world’s caribou herds.

Climate is regional, and weather is local, which is why the dramatic effects of climate change on any given location can be difficult to guess. While we can model and reasonably forecast aspects of climate, inferring how local, idiosyncratic systems will be impacted is very challenging. A group of USGS scientists, working with researchers at the University of Alaska-Fairbanks, have recently completed a preliminary study that illustrates some of the unexpected ways that climate change will impact Alaskan and Canadian caribou herds. Their research, published in the journal PLOSone, shows some surprising effects of climate change in the arctic. Long story short: it ain’t good.

Caribou make their lives in the tough arctic, and their extensive seasonal migrations taking huge herds of these animals across the frozen north in search of food. Many of these herds winter in boreal forests, with their dominant source of winter calories coming from the lichen found there. But climate change could change that.

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As warmer temperatures have crept into the arctic, researchers have noticed increased incidences of wildfires, especially in the boreal forests. The researchers linked the past 90 years of fire data to a suite of computer models, tying fire occurrence in boreal forests to warmer seasonal temperatures across the studied interval. Climate change is bringing even warmer temperatures to the region, and the researchers’ models indicated larger and more sustained wildfires in the future as a result.

For caribou, this will have a dramatic effect. Caribou avoid burned out areas in their winter pilgrimage to the boreal forest, and these changes in migration and herding can persist in the caribou population for many generations. As a result of changing behavior and reduced food availability, the researchers forecast a dramatic decrease in boreal forest caribou populations. The researchers’ model suggests that, by the end of the century, major reductions in boreal forest caribou populations are to be expected as a result of reduced habitat.

Of course, the effects extend beyond just the caribou. In addition to ecological disruption, changes in caribou herds will impact humans as well. The caribou represents an important cultural and caloric resource for many native populations in the region, and many villages, towns, and hunters are linked with annual caribou migrations.

It is also important to note that this study looked only at changes in lichen cover driven be winter temperatures and wildfires. Future work is planned to examine how spring and summer temperature changes will impact the region. The incontrovertible fact is that climate change, which we know will have a dramatic impact on ecosystems and populations, will also drive unexpected changes at the local scale, changes that we are ill-equipped to predict or handle.